Referring to FIG. 5, operations for starting communications in a system of conventional LTE (Long Term Evolution) scheme is described.
As shown in FIG. 5, in step S3000, the mobile station UE performs location registration processing (Attach/TAU (Tracking Area Update)) to the exchange MME of the LTE scheme.
In step S3001A, an application function AP of the mobile station UE transmits “Primitive” to the function EMM performing processing related to the EMM protocol, in response to a calling operation by a user.
Alternatively, the exchange MME in the LTE scheme transmits “S1 Paging” to the radio base station eNB of the LTE scheme in step S3001B, and also transmits “Paging” to the function EMM in step S3001C.
Consequently, in step S3002, the function EMM transmits “Primitive” to the function AS performing processing related to the AS protocol.
In step S3003, the function AS transmits “RRC Connection Request” to the radio base station eNB.
In step S3004, the radio base station eNB transmits “RRC Connection Setup” to the function AS.
In steps S3005 to S3007, the function EMM transmits “NAS Service Request” to the function AS. The function AS includes the received “NAS Service Request” in “RRC Connection Setup Complete”, and transmits the “NAS Service Request” to the radio base station eNB. The radio base station eNB extracts “S-TMSI” from the received “RRC Connection Request”, and also extracts “NAS Service Request” from the received “RRC Connection Setup Complete”. The radio base station eNB includes the extracted “S-TMSI” and “NAS Service Request” in “S1 Initial UE Message”, and transmits the “S1 Initial UE Message” to the exchange MME.
In step S3008, the exchange MME transmits “S1 Initial UE Context Setup” including “UE capability (capability information of mobile station)” to the radio base station eNB.
In step S3009, the radio base station eNB transmits “RRC Security Mode Command” to the function AS, and in step S3010, the function AS transmits “Primitive” to the function EMM.
In step S3011, the radio base station eNB transmits “RRC Connection Reconfiguration” to the function AS, and in step S3012, the function AS transmits “Primitive” to the function EMM.
The function AS transmits “RRC Security Mode Complete” to the radio base station eNB in step S3013, and transmits “RRC Connection Reconfiguration Complete” to the radio base station eNB in step S3014.
In step S3015, the radio base station eNB transmits “S1 Setup Complete” to the exchange MME.
In step S3016, “U-Plane” is established to communicate between the mobile station UE and the network.